1. Field of the Invention
The present invention is directed to structures and methods of (positively or negatively) accelerating charged particles, and in one embodiment to structures and methods of accelerating electrons in an electron beam using a resonant structure which resonates at a frequency higher than a microwave frequency such that the structures and methods emit x-rays in interference patterns that enable the x-rays to be used as a coherent source of x-rays.
2. Discussion of the Background
It is possible to emit a beam of charged particles according to a number of known techniques. Electron beams are currently being used in semiconductor lithography operations, such as in U.S. Pat. No. 6,936,981. The abstract of that patent also discloses the use of a “beam retarding system [that] generates a retarding electric potential about the electron beams to decrease the kinetic energy of the electron beams substantially near a substrate.”
An alternate charged particle source includes an ion beam. One such ion beam is a focused ion beam (FIB) as disclosed in U.S. Pat. No. 6,900,447 which discloses a method and system for milling. That patent discloses that “The positively biased final lens focuses both the high energy ion beam and the relatively low energy electron beam by functioning as an acceleration lens for the electrons and as a deceleration lens for the ions.” Col. 7, lines 23-27.
X-rays are used in a number of medical procedures. Most commonly x-rays are used to examine internal bones or organs to look for abnormalities (e.g., broken bones). Current x-ray sources do not, however, produce coherent x-rays. Coherent x-rays are advantageous in that they have small beam spread, and are more easily manipulated by diffraction, allowing more information to be obtained, or more concentrated doses to be delivered.